A solar thermal power plant includes a large field of heliostats and a solar receiver placed on a tower of substantial height. The heliostats focus direct sunlight on to the solar receiver to produce steam. The steam is utilized to run a turbine and extract work in order to produce electricity. Typically, the solar thermal power plant operates on a daily cycle, during clear sunlight hours, while shutting down in nights or in overcast conditions. However, if the solar thermal power plant is to meet the electricity demand during night and overcast conditions, it needs to be operable irrespective of the availability of solar light, i.e. in nights or in overcast conditions. Most importantly, it improves the dispatchability and hence reduces the levelized cost of electricity. A realization of such a solar thermal power plant generates a requirement of storing solar thermal energy during day times and utilizing thereto in nights or in overcast conditions. For such requirement, a central receiver can be designed to use the medium for thermal storage as the heat transfer medium, such as molten salt or thermal oil/thermic fluid etc. Such arrangement may be evident, for example, in European Patent bearing number 1 873 397 A2 and many others.
A typical receiver system 10, as known in various prior arts, may be evident in FIG. 1. The system 10 includes a receiver 12, hot and cold storage tanks 14, 16, respectively, and a Rankine cycle power block 18 to generate electricity. The molten salt fluid at the receiver 12 is being heated through focusing the sunlight via heliostats 20. The hot salt is stored in the hot storage tank 14, at temperature of about 565° C., and after thermal energy thereof is being utilized by the cycle 18 for producing electricity through generator ‘G’, it is stored in the cold storage tank 16, at temperature of about 290° C., from where it is further sent to the receiver 12 to be reheated.
In such system 10, the design of receiver 12 is very critical for efficiently operation of the system 10.